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During our working hours, we all need a refreshing breath of fresh air on our table. ImagineĀ being able to obtain it with the help of a fridge magnet! To enhance it further, you also have aĀ small LED light that switches on while the fragrance is sprayed.Ā
A 2 way operation module is presented wherein by activating the reed switch, a Spray and aĀ Light assembly can be put ON for a duration of 3-5 seconds. In the second choice, where aĀ switch button is employed, the spray stops (after 3-5 seconds) but the LED continues to glow.Ā This can actually double up as a Night Bedside Lamp cum Room Freshener with your favouriteĀ choice of scent.Ā Ā
The proposed setup is used as a combined spray and light assembly. Figure 1 shows the authorāsĀ prototype of the entire setup. Figure 2 represents the block diagram of the Project.Ā Ā
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The motor used in the proposed setup is a modified motor. We have used the gear combination found in Home Millerās 250V motor. We applied that gear combination on a 4000 RPM 12VĀ DC motor and attached one round-end effector. Our purpose for it was to activate the RoomĀ Freshener by giving one full rotation to the motor. Torque was the main reason to chooseĀ Millerās motorās gear combination.
We used 555 Timer IC, which is a popular integrated circuit (IC) that is widely used in electronic circuits for timing and oscillator applications. The IC consists of comparators, flip flops, resistors, and transistors, all integrated onto a single chip. It is available in different packages, including DIP (dual in-line package) and surface mount versions, making it easy to use in various circuit designs.
Additionally, IRFZ244, a specific model of a power MOSFET (Metal-Oxide-SemiconductorĀ Field-Effect Transistor) that is commonly used in electronic circuits for switching applications, is used for switching. It is commonly used in applications where high power switching is required, such as motor control, power supplies, inverters, and amplifiers.
We used a Reed switch as a secondary switch, which is also known as a Reed contact. It is an electrical switch that operates based on the magnetic field. It is made up of two ferromagnetic reed blades enclosed in a glass tube filled with an inert gas. When no magnetic field is present,Ā the reed blades remain separated, and the switch is in an open state, which means it does not conduct electric current. However, when a magnetic field is applied (in the present case using the fridge magnet) near the reed switch, the magnetic force causes the reed blades to attract and make contact with each other, closing the switch and electric current flows. Figure 3 shows the working principle of a reed switch.
The Circuit is very simple to operate. You can refer to figure 3 for the Circuit diagram andĀ figure 4 for the connection of the proposed solution.
Table 1Ā
ComponentsĀ |
AmountĀ |
Description |
555 Timer ICĀ |
Rs. 8Ā |
IC that controls the ON-OFF signals |
IRFZ244Ā |
Rs. 32Ā |
Power Mosfet |
CapacitorsĀ |
Rs. 40Ā |
High Initial torque |
ResistorsĀ |
Rs. 30Ā |
Biasing |
Modified MotorĀ |
Rs. 450Ā |
To activate the Room Freshener by press |
SwitchĀ |
Rs. 18Ā |
To On and Off circuit |
Reed SwitchĀ |
Rs. 19Ā |
Power On or Off using magnet |
LEDĀ |
Rs. 9Ā |
To Light up |
12 V DC AdapterĀ |
Rs. 199Ā |
To power up the circuit |
Total: 805/-
Working
Upon activating any of the switching techniques, the room freshener will be dispensed once,Ā simultaneously coinciding with a single rotation of the motor. Let us examine the step by stepĀ process.Ā
- The motor is interfaced with the power supply using a MOSFET and a 555 Timer IC.Ā The switch and reed switch are connected in parallel, such that either of them in a highĀ state will activate the circuit. One terminal of the switches is linked to the positiveĀ terminal of the power supply with a resistor (47 KĪ©), while the other terminal isĀ connected to Pin 2 through capacitor (10 uF), which corresponds to the Trigger Pin ofĀ the 555 Timer IC.Ā Ā
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Pin 8 of the 555 Timer IC is connected to the positive terminal of the power supply,Ā while Pin 1 is connected to the negative terminal. The Discharge Pin (Pin 7) and theĀ Threshold Pin (Pin 6) of the 555 Timer IC are connected through a resistor (10 KĪ©),Ā and a capacitor (200 uF) is placed between Pin 6 and Pin 1.Ā Ā
- The Output Pin (Pin 3) of the 555 Timer IC is connected to the Gate Pin of the IRFZ244.Ā A pull-down resistor (10 KĪ©) is added between the Gate Pin of the IRFZ244 and theĀ Ground Pin (Pin 1) of the 555 Timer IC. The Source Pin of the IRFZ244 is alsoĀ connected to the Ground of the 555 Timer IC (Pin 5) through a capacitor (0.001 uF).Ā The Drain Pin of the IRFZ244 is linked to the positive terminal of the power supply,Ā and the motor is connected between the Drain Pin of the MOSFET and the negativeĀ terminal of the power supply with a capacitor (100 uF).
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To achieve a specific delay that allows the motor to complete one rotation, resistors andĀ capacitors are incorporated into the circuit. The timing formula for the 555 Timer IC inĀ monostable mode, t = 1.1 Ć R1 Ć C1, provides the desired delay time for a one-timeĀ turn-on event.Ā Ā
An LEDlight is integrated into the system to indicate the circuit’s state and also to provide aĀ source of light in case the system is kept in darkness.Ā
On a conclusive note, it is a wonderful personalized low cost alternative to the existing choicesĀ available in the market.Ā